Temperature regulator



Nov. 24, 1936. F. F. UEHLING TEMPERATURE REGULATOR Filed March 7, 1935 3 Sheets-Sheet 1 Nov. 24, 1936. F. F. UEHLING 2,061,884

TEMPERATURE REGULATOR Filed March 7, 1935 3 Sheets-Sheet 2 Patented Nov. 24, 1936 UNITED STATES PATENT OFFICE 2,061,884 Tmmrnnanacum'roa ma Merisi: Uehunraaaie, N. J. sppucauon March 7. 1935, serial No. 9,909 zoclsims. (onzas-7s) This invention relates to improvements in automatic regulators which utilize a galvanoxneter as the element responsive to changes in the variable regulated. More particularly it provides a novel combination of relays and circuits which relaysare actuated by the galvanometer to operate'the regulating means. Furthermore the needle of the galvanometer which makes electrical contact to actuate the relays is intercepted by a movable contact piece which is forced out of and into the path of the needle only when the galvanometer is affected by changes in the variable regulated. This, in combination with a novel contact method, eliminates the necessity of a continuous cycle of motion such as is essential in other types of regulators which utilize the galvanometer as the actuating means. A novel arrangement is also provided for anticipating changes in the variable regulated thereby preventing overstepping or hunting. v

Figure l is a diagrammatical illustration which shows all of the essential elements in elevation with their electrical interconnections; Figure 2 illustrates the relay which actuates the contact piece,l and shows the relation of the contact piece with respect to the galvanometer needle. in a position opposite to that illustrated in Figure l; Figure 3 is a plan view of the galvanometer with the needle in one of its positions with respect to the contact piece; Figure 4 is a plan view of the galvanometer in another of its positions with respect to the contact piece; Figure 5 illustrates two of the relays'with their various switches in one of their respective podtions; Figure 6 illustrates the same relays `with the switches in another of their respective positions; Figure I illustrates a special form oi' variable potentiometer in one of its positions; Figure 8 illustrates the same potentiometer in another of its positions: Figure 9 illustrates two of the relay switches in combination with the motor-operated valve which is actuated by said switches: Figure 10 illustrates another position of the same relays shown ln Figures 5 and 6. -Similar numerals represent similar parts throughout all of the illustrations.-

A galvanometer Figures 1, 3. and 4. consisting of a coil 5 pivoted or suspended between the north and south poles, and 2 respectively, of a permanent magnet, is utilized as the actuating means of the regulator and may be influenced by variations in whatever physical condition is to be controlled. Although a galvanometer may be directly or indirectly inuenced by a large variety of physical variables. I have chosen for the purpose of illustration. an electric furnace 88, the

temperature of which inuences the galvanometer by meansof a thermo-couple'9l, the electro-motive force of which couple detlects the gaivanometer as required to actuate the regulator to maintain the desired temperature in the furnace. 5 lThe circuit which includes the furnace starts at a battery or any other source of energy 89, thence through wire 90 to a switch consisting of a contact spring 62 and a contact piece 85. 'Ihis switch will be hereinafter referred toas switch 62-85. From this switch the circuit continues through wire 84 `to the furnace, and from the furnace through wire 88 back to the batte The circuit which includes the couple and the galvanometer starts at the couple 9|, and thence through wire 92 to a contact spring 39. Whe:` the contact spring 39 touches a contact piece 45 as illustrated in Figure 1, the circuit continues from contact spring 39 through the contact piece I5 and the wire 93 to a variable potentiometer |08, through which potentiometer it continues from the point to an adjustable brush 94, and thence through wire 95 to the point |28. The contact spring 39 and the contact piece 45. above mentioned, will hereinafter be referred to as switch 39-45. Similarly when the contact spring touches a contact piece I4 as illustrated in Figure 6, the circuit continues from the contact spring 39 through the contact piece Il and the wire I I 4, Figure 1, to another variable potentiometer |01. through which potentiometer it continues from thev point ||2 to an adjustable brush H5 and thence to the point |28. I'he contact spring 39 and the contact piece u willl hereinafter be referred to as switch 39-14. This switch and the switch 39-45 thus act respectively to close the through the potentiometer |01 or the potentiometer |08 dependingupon whether the magnet 21 is deenergized or energized. The purpose of the two potentiometers |01 and |08 and the switches 39-44 and 39-45. and the manner in which the magnet 21 is energized will be presently described From the point |28 the thermo-couple circuit continues through wire 98 to another variable potentiometer |82 through which it continues from the point H3 to an adjustable brush 91. from the brush 91 through wire 98 to an adjustable resistance |21. and thence through the wire H9. the galvanometer 5 and the wire 99 back to the couple. The thermo-couple 50 circuit is illustrated by means of a dotted line so that it may be readily distinguished from the rest of the circuits. The purpose of the potentiometer |82 is to set the regulator for the temperature at which the furnace is to be maintained. Refer- 55 electro-magnet 21.

ence will again be made to both the potentiometer |62 and the resistance |21.

A combination of switches, Figure 1, which consists of a series of contact springs 31, 38, 39, 40 and 4|, and a series of contact pieces 42, 43, 44, 45, 46, 41, 48, and 49, are operated by the Said contact springs are held in one position, Figure 1, against their combined tension by means of an arm 29 which forces them into the position illustrated through insulation pieces 32, 33,'34, 35 and 36 when the magnet 21 is energized. -The switches consisting of contact spring 31 and contact piece A42.' contact spring 38 and contact piece 43, contact spring 48 and contact piece 46, contact spring 40 and contact piece 41, contact spring 4I and contact piece 48, and contact spring l4I and contact piece' 49,

will hereinafter be referred to as switches 31-42,

38-43, 40-46, 40-41, 4I--48 and 4I49 respectively.

An armature 28 which 21, is an integral part of the arm 29 and is pivoted at 30, as illustrated, so that when the magnet is energized, the switches 31-42, 39-44, 40-46, and

35i- 45, 40-41 and 4I-49 closed. On theother `hand when the magnet 21 is deenergized, and

when the amature 28 is free to return to its normal postion,.it will be forced to that position, as illustrated by Figure 6, by the tension of the contact springs 31, 38, 39, and 4I through the insulation pieces 32, 33, 34, 35 and 36 in which position the switches 3142, 35i- 44, 40-46 and 4I-48 will be closed and the switches 38-43, 39-45, 40-41, and 4I-49 opened. All of the switches actuatedby the magnet 21 are supported and insulated from each other by an insulation piece 50 which at the same time supports the magnet 21 and insulates the magnet connections 56 and 51.

A second electro-magnet 5I, Figure 1, which operates another combination of switches is provided with an armature 52 which armature is an integral part of an arm 54 and is pivoted, as illustrated, at 55. The armature 52 is provided with a catch 53, while the armature 28 is provided with an extension 26. The relative positions of the electro-magnets 21 and 5| are such that if the magnet 21 is energized while the magnet 5I is deenergized. the catch 53 and the extension 26 will act as a latch to prevent the return of the armature 28 to its normal position when the magnet 21 is deenergized as illustrated in Figure 5. The purpose of this latch, and the effect which the energized, deenergized and latched positions have on the switches will be presently described. The combination oi four switches which are operated by the magnet 5I, consist of a series of contact springs 6|, 63. and 62, and a series of contact pieces'64, 65 and 66. These switches which consist respectively of contact spring 6| and contact spring 63,- contact spring 63 and contact piece 64, contact spring 62 and contact piece 65. and contact spring 62 and contact piece 66, will hereinafter be referred to as switches 6I--63, 63--64, 62-65 and 62-66. When the magnet 5I is deenergized, the switches 63-64 and 62-55 will be closed, and the switches 6I6Iiv and 62-66 opened, as illustrated in Figure l. Similarly whenl the magnet 5| is energized, the arm 54 will force the contact springs to one side through insulation pieces I I6 and I I1 thus closing the switches 6'I-63 and 62--66 and opening the switches 63-64 and 62--65 asillusreacts with the magnet 5|, Figure 1, are opened and closed by means of a switch consisting of a contact spring 23 and contact piece 22. This switch will hereinafter be referred to as switch 22-23. andis operated by'an electro-magnet I2 through an extension arm I4 and an insulation piece 24. The extension arm I4 is an integral part of an armature I3 which is pivoted at 26 so that when the magnet is energized, the switch will be open as illustrated in Figure 2, and closed as illustrated in Figure l when the magnet is deenergized. Fastened to the upper end of the extension arm I4, as illustrated, is an electric contact piece I5, which is insulated from the arm I4 by means of an insulationpiece I6. The normal position of the contact piece I5, as illustrated in Figures l, 3 and 4, is such that the galvanometer needle I0 will be intercepted by the contact piece when the needle is deflected in one direction or the other depending upon which side of the contact piece theneedle is at the time. However when the contact piece is forced-down by the magnet I2 as illustrated in Figure 2, the needle will be free to move in either .direction without interception.

The purpose of the contact piece I5 and the manner in which electrical contact is established between it and the -needle will be presently described.

The circuit which includes the magnet |2 also includes the galvanometer coil 5, the needle I0, and contact piece I5, a battery 61 and the combination Yof switches 40-46. 40-41, 4I-48 and -4I49. The purposey of these switches is to change the polarity of the battery 61 from one direction to another depending upon whether the magnet 21 is energized as illustrated in Figure l, or deenergized as illustrated in Figure 6. There are therefore really two circuits, each of which includes the galvanometer coil 5. the needle I0, the magnet. I2 and the battery 61, the first of which includes the 'switches 40-41 and 4I-49 and through which circuit the current'ows in one direction. and the second of which circuits includes the switches '40-46 and 4I-48 and through which second circuit the current iiows in the opposite direction. Thus when the magnet 21 is energized, the circuit starts at battery 61, thence through wire 68 to the switch 4I-49, from the switchthrough wires II8 and 12 to the magnet I2, from the magnet I2 through a nexible connection I9 to the contact piece I5, and when the needle I6 touches the contact piece I5 the circuit continues through the needle to the galvanometer coil 5, thence through wires 13 and 10 to the switch 4-41, and from the switch through wire 69 back to the battery. On the other hand when themagnet 21 is deenergized. the switches 40-46 and 4I-48 will be closed, Figure 6, and the battery will supply current through the galvanometer and the magnet I2 in the opposite direction. This circuit starts at bat- 2,061,884 l and 1| so tue-switch Mangue 6 and fromj 111e switches actuated by the electro-magnet Si.

position. Figure e, the switch si-ss win-be One position, when' the magnetii is is illustrated by Figures 1, '5 and 10, andthe other position when'the magnet 5| is energized, is illustrated -by Figure. ilrst or de- 'energized position the switch.6I-63 will be, Open and the switches ss-sa and sz-ss wm be clos-eg. On the other. hand in the second or energizedand the switches 63-84 and 62-65 will be open. The switches actuated by the electro-magnet will have, however, three dierent positions, one in which the electro-magnet 21 isenergized as illustrated in Figure 1, a second position in which the magnet 21 is deenergized but ln which position the armature 28 is held by thelatch as illustratedin Figure 5, andthe third position in which the latch has been released thereby permitting the armatm'e 28 to vmove .to its'completely open position as illustrated-in Figures 6- and 10. In the ilrst of said three positions the switches 31-42, 391-44, 40-46, and "-48 wlll'be open and the switches 38-43, 39-45, 40-41, and 4|.-49 will be closed. In the second or latched position, was illustrated in Figure, the 31-42 will be closed due tothe slight motionjof the armature 28 from its energized-position to its latched pontion. This small motion of the amature vwill howeverinot aifect 4the open or closed positions of the remaining switches which will remainthe sameasillustratedinFigure-l. The clomng of the 'switch 21-42 by the motionv of the amature from its energized to its latched position without aifecting the remaining switches is an important part of this invention and will be referred to again in connection with the circuit which includes this switch. -In the'third or unlatched position as illustrated in FlguresG and 10 the switch 31--42 will obviously still remain closed while switches 29-44, 40-46 and "-48 will also be closed andthe switch 38-43,' 38-45, 40-41 and "-49 will be Open- The circuits which include the electro-magnet 5| and the elect ro-magnet` 21 will be open and closed primarily by the switch 22-23 which switch as previously stated is operated by the electro-magnet i2. The energy' which-actuates the magnets 5I and 21 is supplied by the battery G1. When'both the magnets 5I and 21 are deenergized. the armatures 52 and 28willbeinthe positions illustrated in Figures 5 or 10 depend-A ing upon whether the armature 28 is in its latched or unlatched position. With said arma.-

tures in the-positions illustrated in Figure 10,` the electro-magnet 21 will be energized when the switch 22-23-is closed through the circuit which starts at battery 61,.Figure 1. thence through' wire 14 to the switch 22-23. from this switch through wires 15 and 82 to the electro-magnet 21. Figure'lo, from the magnet-21 through wires switchi-N throughwirelLFgurel. backto the battery. The closing of this circuit energizes the `magnet 21 to force the switches actuated thereby into the positions illustrated in Figure l.

If now the. magnet l2 be energized thereby opening the circuit, just traced and which in- .wires 1s Yand n m'theswl' .latch by 'the magnet 5i which in the circuit Just traced, xvill permit the armature .andwiret'L 3 cludes the magnet 21,' the armature 28 will be free to move to its`latched position as illustrated in Figure 5 in which latched position the 'switches 2l-'42 and 38- 43 will be closed as illustrated. If

now the magnet l2 is deenexgized, the switch.

22-'23 will mln elosebut this time the circuit which it closes will include vthe magnet 5| which when will the latch 'to permit the armature 28 and the switches operated thereby to return to the position illustrated in Figure 6. 'rms circulrwhich includes the magnasi starts at battery 61, Figure 1, thence throughwire 14 to the switch 22-'23. iromihls Switch through Wire 15 to the magnetii, from the magnet 5i through 31-42, Figure 5. from this switch thnough wire 18 to switch 38-43, thence through thewires'19 and 63-64 and from this switch.

wire" backtothebattery.

Figure 1, through The releasing ot the 28 to return to the-position illustrated in Figure 6. In this position the vswitch 38-43 which is includedin the circuit last traced, will be open. The magnet 5| will however remain energized due to thes'witch 6|'63 which, in the position illustrated in Figure 6 closes a holdingcircuit which starts at battery 61, Figure l. thence through wire 14 to the switch 22A-23, from this switch through wire15 to the magnet 5|, from the magnet 5l through the wire 16, Figure 6, to the switch 6 I-63. and from'this switch'through wire 8i back to the battery, The contact Vspring 63, as previously stated, is so shaped that the switch 6I-63 closes before the switch (i3-$4 opens. thus closing said illustrated in Figure 5. when the magne: 5I is first energized. current will also iiow through the magnet 2 1 through wires 15, 82, 83. 80. switch 63-64 The magnet 21 is, however, provided with a. copper slug 3| which retards its reaction with the armature 28. 'Ihe magnet 5|, however, reacts withA its armature immediately thereby breaking the circuits through the switch 63-64 before the magnet 21 has time to act, and simultaneously closing the holding circuit which as statedV keeps the magnet 5| energized to hold thc switches in the positions illustrated in Figure 6. If the switch 22-23 be now open. the magnet 5 i will be deenergized and the switches actuated by magnets 5I- and 21 will assume the positions illustrated in Figure 10. The next closing of the switch 22-23 will however again energize the magnet 21 Ywhich in the manner already stated `will reestablish the switches in the positions illusmagnet is included.

to the switch Figures 10, l, 5 and 6 respectively, this cycle consisting cffour denite steps, repeating itself continuousiy so long as the consecutive opening and closing of the switch 22-28- continues. In other wonis when the switch 22-23 is opened and closed the tlrst time. the switches operated by the magnets 21 and 5l will take the positions illustrated in Figure 6. and when the switch 22-23 is opened and closed the second time. the switches operated by the magnets 21 and 5l will take the positions illustrated in Figure i. It therefore follows that as the magnet l2 is :"peatedly energized and deenergized. the switches operated by the magnets 2`IA and:`5I will change from lone to the other of thetwopositions illustratedin Figures land 6 meegeven-.2

.A Y.. The armature.) 3 when it reacts with themagnet I2 also.;lowe rs the contact piece I5 so that it will bet'eiow. thefpanein which the-needle" "f the V.tact between the needle Iliandthe contact piece I5 has been established the switches operated by the magnets 2l and 5I are in the positions illustrated in Figure l. The delicate force of the galvanometer needle against the contact piece I5 will close the circuit (already traced) through the galvanometer coil 5 and the magnet I2. Due, however, vto the delicate force of the needle, in-

Vsuilicient current will flow through the circuit to actuate the magnet I2. With'the switch positions as illustrated in Figure l, the switches lll-4l and 1I- 49 will be closed which provides thc proper polarity from the battery 61 to cause a current ow through the galvanometer coil 5 in the proper direction to force the needle i tighter against the contact piece I5. This increased pressure will obviously decrease the-contact resistance between the needle I0 and the contact' piece I5 thus increasing the' current flow through the circuit which includes the galvanometer coil and the magnet I2, thereby still further increasing the pressure between the galvanometer needle and the contact piece I5 thus continuously decreasing said contact resistance until suiicient current flows through the magnet I2 to open the switch 22-23, and pull the contact piece I5 down below the path of the needle as illustrated in Figure 2. As soon as the contact piece I5 is below the path of the needle, the latter, due to the force with which it rested against the contact piece, will snap to some new position a, Figure 3,'to which position, as illustrated by the dotted line, it Vwill be carried by inertia. The breaking of the contact between the needle I0 and the contact piece I5 will deenergize the magnet I2 thus again closing the switch 22-23 and permitting the contact piece I5 to return to its normal position as illustrated in Figure 1. The opening.and closing 'of the switch 22-23 thus effected will have caused the switches operated by the' magnets 21 and 5I to shift to the positions illustrated in Figure 6 in the manner previously stated. After the contact piece has thus returned to its normal position, the

galvanometer needle will obviously be on the.

opposite side of the contact piece so that when it is deflected in a clockwise direction it will make electrical contact with the contact piece I5 as illustrated in Figure 4. When contact has thus been established, by the delicate force of the needle, the circuit through the magnet I2 and the galvanometer coil 5 will be closed. Due, however, to the delicate force of the needle, insufiicient current will flow through the circuit to actuate the magnet I2. The switches d0- 46 and 4I-48, as

' illustrated in Figure 6, will however now be closed thusreversing the polarity of the current flowing from the battery 61 so that the current flowing through the galvanometer coil 5 will force the needle tighter against the contact piece is. 'rms increased pressure will obviously decrease the contact resistance between the needle I0 and the contact piece I5 thus increasing the currentflow through Athe circuit which includes the galva- -nometer coil 5 and the vmagnet I2, thereby still further increasing the pressure between the galva- `nometer needle andthe contact piece I5 Idius continuously decreasing said'contact resistance until sufficient current flows through the magnet I2 to y open the switch 222-23 and again pullthe contact piece I5 down below the path of the needle as illustrated vin Figure-2.- As soon as the contact piece I5 is below the path of the needle, the latter, due to the forcel with which it rested against the contact piece will snap to some new position b,

A Figure 4, to which position as illustrated by the dotted line it will' be carried by inertia. The breaking of contact between the needle I0 and the contact piece ,I5 will deenergize the magnet I2,

thus again closing the switch 22--23 and permitting the contact piece I5 to return to its normal position as illustrated inFigure 1. The opening and closing of the switch. 22-23 thus effected will have caused the switches operated by the magnets- 2I and 5I to return to the positions illustrated in Figure l in the manner previously stated. After the contact piece has thus returned to its normal position, the galvanonieter. needle will obviously be again on. that side of the contact piece I5 as illustrated in Figure 3` so that when it is again deflected in a counter-clockwise direction suilicintly to touch the contact piece I5, the switches operated by magnets 21 and 5I will again be shifted to the position illustrated in Figure 6.

1t win be noted that the galvanomecer con 5 is included in both the circuit which includes the magnetl I2 and the circuit which includes the thermo-couple. In other words the coil 5 and the thermo-couple circuit are in parallel so that the current from the batteryGI for energizing the magnet I2 .actually divides itself into two paths after it vpasses through the needle, one path through the galvanometer coil and the other path through the thermo-couple. The adjustable resistance I2`I, already referred to, may therefore be increased or decreasedas required to make the contact pressure betweenthe needle and the contact piece I5 more or less as desired.

Let us assume that the zero or null position'of the indicating needle IIJ is suchv that the axis of the needle coincides with the'axis of the contact piece I5. Under these conditionsif the needle were manually forced to the position a, Figure 3, it would naturally return clockwise until intercepted by the contact piece I 5, Figure 4, by means of which contact piece, its return to the above assumed null position would be prevented. Similarly if the needle were manually forced to the position b, Figure 4, it .wou1d naturally return counter-clockwise until intercepted by the contact piece I5, Figure 3, by means of which contact piece its return to the above assumed null position would be prevented. In other words if the zero or null position of the needle I0 is such that its axis coincides with the axis of the contact piece I5 it will always come to a position in which it touches one side or the other of the contact piece I5, as long as there is no current flow through the galvanometerv coil. As -previously stated, however, the galvanometer 'circuit which includes the couple 9|, also includes one or the other of the potentiometers |01 or |08, vFigure 1, depending respectively upon whether the switch 39-Ii4 or the switch'39-45 is closed. It therefore follows that if the potentiometers |01 and |08 are adjusted to their zero positions as illustrated in Figure 7, and if there is no electro-motive force created by the couple, then the switch 22-23 will continue to open and close due to the contact which the needle makes with the contact piece I5 alternately in clockwise and counter-clockwise directions.

When the needle is on that side of the contact piece I5 as illustrated in Figure 3, the switches operated by the magnets positions illustrated in Figure 1, in which positions the switch 39-45 will be closed to includ: the potentiometer |08 in the couple circuit.- With the potentiometer properly adjusted as illustrated by Figure 8, and under the asumption that there is no other active source of electrical energy in the thermo-couple circuit then the drop across this potentiometer will be just suicient and in the proper direction to deflect the galvanometer. needlel clockwise from its zero position to prevent electrical contact between the needle and the contact piece I5. Figure 3, and to establish a very minute gap between said needle and the contact piece. In other words when the switch 39-45 is closed as illustrated in Figure 1. the position of the needle with respect to the contact piece I would be as illustrated in Figure 3 except that the drop across the potentiometer I 08 would be just suicient to deflect the needle clockwise to a position in which it just fails to touch the contact piece.

when there is no other active source of electromotive force in the galvanometer circuit. Similarly when the needle is on that side of the contact piece I5 as illustrated in Figure 4, theswitches operated by the magnets 2`| and 5| will be in the positions illustrated in Figure 6 in which positions the switch 39-44 will be closed to include the potentiometer |01 in the couplecircuit. With the potentiometer |01 properly adjusted as illustrated in Figure 8, and under the assumpt'on that there is no other active source of electrical energy in the thermo-couple circuit then the drop across this potentiometer will be liust suilicient and in the proper direction to deflect the galvanometer needle counter-clockwise from its zero position to prevent electrical contact between the needle and the contact piece I5, Figure 4, and to estab-- lish a very minute gap between said needle and contact piece. In other words when the switch 39-44 is closed 'as illustrated in Figure 6, the position of the needle with respect to the contact piece I5 will be as illustrated in Figure 4 except that the drop across the potentiometer |01 will be just suiiicient to deect the needle counterclockwise to a position in which it just fails to touch the contact piece when there is no other active source oi' electro-motive foi-ce in the galvanometer circuit.- It therefore follows that when the brushes 94 and III are adjusted as illustrated in Figure 8, the galvanometer needle I 0 will just fail to touch the contact piece I5, Figure 3, when the switches operated by magnets 21 and 5I are in the positions illustrated in Figure 1, audit will just fail to touch the contact piece I 5, Figure 4. when the switches operated by the magnets 21 and 5I are in the positions illustrated in Figure 6. In other words when there is no electro-motive force from the thermo-couple, the needle I0 will just fail to touch the contact pie I l regardless of what side of the contact piece the needle may be (Figures 3 and 4).

The polarity of the couple 0I is such that as the temperature of the furnace 06 increases, the needle oi' the galvanometer will deiiect counter- `ly referred to, has a 21 and 5I will be in thev clockwise, and as the temperature of the furnace decreases the needle of the galvanometer will deect clockwise. The potentiometer I 02. previouspolarity opposite to that oi' the couple, and may be adjusted to balance the electro-motive force of the couple for any given temperature of the furnace. Let us assume that the potentiometer I 02 has been adjusted to balance the electro-motive force of the couple when the temperature of the furnace is 500 degrees. Under these conditions, as the temperature of the furnace increases, and with the potentiometexs |01 and |08 adjusted as above stated, Figure 8, the needle will deflect counter-clockwise toward the contact piece I5, and when the temperature is just a shade less than 500 degrees the galvanometer needle will be in the position illustrated in Figure 3 except that the needle will not be deflected quite suillciently in a counter-clockwise direction to make electrical contact with the contact piece I5. Furthermore with the needle in that position, the switches operated by the magnets 21 and 5I will be in the positions illustrated in Figure l. In this position the furnace circuit ypreviously traced will be closed by the switch 62-65 under which condition the furnace temperature will obviously increase until 500 degrees has been reached, at which temperature contact will be established, Figure 3, between the galvanometer needle and the contact piece I5. 'Ihis will close the independent circuit, previously traced, through the galvanometer coil 5 which circuit includes the magnet I2, the battery 61, and the switches lli-41 and 4I-49 which switches, in the manner previously stated, establish the proper polarity from the battery 61 to force the needle I0 tighter against the contact pie I5 in a. counter-clockwise direction. 'I'he I5 continually increases, in the manneralready stated, until suiiicient current iiows through the magnet I2 to open the switch 22-23 and to pull down the contact piece I5 to a point below the plane in which the needle I0 moves. Ihe breaking of contact between the needle and the contact piece I5 when the magnet I2 is energized will, in the manner previously stated, cause the needle temporarily to be forced to the position a, Figure 3, and simultaneously to deenergi the magnet I2, thereby allowing the contact piece I5 to return to its normal position, as illustrated in Figure l, and again close the switch 22-23. The opening andclosing of switch 22-23 will, in the manner previously stated. cause the switches operated bythe magnets 21 and 5I to-shiit to new positions illustrated in Figure 6. In these positions the thermo-couple circuit will include the potentiometer |01 instead of |08 due to the closing of the switch 39-44. The switch 62-65 will be open to deenergize the furnace, and the switches 40-46- and 4|48 will be closed to change the polarity of the circuit which includes the galvanometer needle and the contact piece I 5.

Due to the heat still in the resistance wires of the furnace after the heat has been turned oil, the temperature of the couple will obviously increase to some point beyond the 500 degrees for which temperature the adjustable potentioxn, eter |02 was set. Due to the fact, however, that the furnace circuit is open through the switch 62-65. Figure 6, the temperature of the furnace and the couple 9| will gradually recede thus causing the needle of the galvonometer to deflect in -a clockwise direction until the temperature of the furnace drops to exactly 500 degrees at u the contact piece I5 in a clockwiseV direction,

the pressure between the needle and the contact piece I5 continually increasing ,in `the `manner previously described, until. sulcient current flows through the magnet'IZ to again' open the switch 22-23 and to pull down the contact piece I5 to a point below the plane in which the needle needle Illand contact-piece i5 when themagnet I2 is energized will, as previously -s tated,' cause the needle temporarily to be forced to the posi-` tion b, Figure 4,'and simultaneously to again deenergize the magnet I2, thereby allowing the contact piece l5 to return to its normal position as illustrated in Figure l, and to lagain close.l

the switch 22-23. The opening and closing of the switch 22-23 will this time, in the manner previously described. causethe switches operated by magnets 2`I and 5I to shift back to-the positions illustrated in Figure 1. In these positions the jcouple circuit will'again include the potentiometer |08 instead of potentiometer |01 due to the closing of the switch :Q 45. The switch 02-65 will again be closedto energize the furnace, and the switches 40-41 and 4I--49 will again be closed to effect the proper polarity of the circuit which includes the magnet I2 to insure electric contact between the needle and the contact piece I5, when the temperature of the furnace again reaches 500 degrees. Due to the cooling rate ofthe furnace when the furnace circuit is open, the temperature of the couple may drop somewhat below 500 degrees, for which temperature as previously stated the potentiometer |02 has been set. Due to the fact, however. that the furnace circuit is now again closed through the switch G2-6 5, Figure 1, the temperature of the furnace and the couple 9| will again rise thus causing the needle of the galvanometer to again deflect in a counter-clockwise direction until the temperature of the furnace again reaches 500 degrees at which temperature the needle I will again make contact with the contact piece I5, Figure 3, to again shut oiI the furnace in the manner above stated.

It thus follows that when the temperature of the furnace is below 500 degrees, for which the potentiometer |02V has been set, the indicating needle .I0 will be` on that sideof the contact piece I as illustrated in Figure 3, and when the temperature increases to 500 degrees the needle will make electric contact with the contact piece I5, in a counter-clockwise'direction thus closing the actuating circuits which operate the relays in the manner described to open the furnace circuit. Similarly when .the temperature of -the furnace is above 500 degrees, the' indicating needle i0 will be on that side of the contact piece asillustrated in Figure 4. and. when the temperature drops to' 500 degrees, the needle will make electric contact with the contact piece I5 in a clockwise direction thus closing the actuating circuits which operate the relays in the manner described to close the furnace circuit. The furnace will therefore be kept at a constant temperature within the overstepping characteristics of the furnace itself, said constant temperature being 'determined by the setting of the potentiometer The primary purpose of the potentiometers |01 5 and |00 in combination with the switches 38-44 and 30-45 is to provide suilicient electro-motive force in the'proper. direction to just prevent the galvanometer needle touching the contact piece `i5 when the eceltrc-motive force of the couple 10 is balanced bythe potentiometer |02, and regardless of whether the-needle is onone side or the other of said contact piece..` The manner in which this is accomplished-hasalready been ldescribed. The same combination of potentiom l5 eters and `switches mayhowever. al so be utilized-toprevent ,overheating or over cooling of moves. The breaking of the contact betweenrthe` the furnace such as itgenerally experienced to a more orl less degreewith' all off and on types of temperature As previously stated, 2.0 due to the pressure fof the needle. against the contact piece I5 in.f..one direction or the other as caused by the. circuit. which includes the magnet I2, the needle I0, 'and the galvanometer coil 5,

the needle will snap Aizopositionja. Figure 3, or

to a position;b,-Figure 4,. depending upon which side of the contact piece I5 thev needleis atl the time contact is established. The galvanometer is however dampened. electrically or otherwise,

so that a measurable time increment elapses before the needle returns to its correct position as determined by the amount of current flowing through the thermo-couple circuit. The time required for the needle to deflect from the position a, Figure 3. until it again touches the contact piece I0 Vas illustrated in Fi'gure 4. may for vexample be reduced to any magnitude even to practically instantaneous action by adiustlng 'the potentiometer I0I in the proper direction.

The return ofthel needle to the position illus- 40 trated in Figure 1 may'also be delayed as much as desired by, adjusting the same potentiometer in thev opposite direction. Similarly the time required for the needle to deflect from the position b, Figure 4, until it again touches the contact piece IS as illustrated .in Figure 3, may be reduced to any magnitude, even to practically instantaneous action by adjusting the potentiometer |00 in the proper direction, and the return of the needle to the position illustrated in Figure '3, may also be delayed as much as desired by adjusting thesame .potentiometer in the opposite direction. It therefore follows that the time required forturning on the heat input to the furnace after it was turned 0H bythe regulator may be influenced in one direction or the other by adjusting the potentiometer. |08, and the time required for turning off the heat input to the' furnace after it has been turned'on by the regulator may be inuencedfin one direction orA the c, other by adjusting the potentiometer I0`I.- The regulator may thus be adiusted to suit the par-` 2,061,884 steam valve |26'which -is operated bya reversible motor lzlthrough a gear box |25, andthrough -which steam may be turned oif or on as required to maintain a constant temperature in some chamber not shown; .The switches 62-65 and 62-56, Figure 9,-are thesameas illustrated in Figure 1. The circuit for operating the motor lto open the valve includes the battery .|22 and the thus described-muovermi@ what I 1.v In a device-ofthe class described. the combination with an armature, of a spring arrangement for Aholding the "armature initsnormal position, 'anelectro- 'et for pulling the arma-- ture f away from'` its normal position to a.' second position, a latch for'pre'venting the return ofthe amature -to its normalposition after` the magnet has been. deenergized but permitting aslight motion toward normal to a Athird position, a second .electro-magnet Afor releasing the ,latch to permit the to return toits normal position.- a which is opened by the'armature when the armature is in its second position and closed when the amature is in its third and normal position, a second switch which is closed by the armature when the armature is in its secondand third positions and opened when the armature is in its normal position. a third switch and a fourth switch which are opened 'and closed respectively by the' second magnetwhen the magnet is energized, and Vclosed and opened respectively when the magnet is deenergized, Ameans -for closing the fourth switch before the third switchlis opened as the second magnet is energized, and means for closing the' third switch before the fourth switch is opened as the second magnet is deenergized. a4 galiza-rieur eter. a fifth switch controlled 'by the'galvanometer, a4 circuit which includes the ilfthswitch. the third switch andthe first magnet, a second circuit which includes the iifth switch. the third switch, the second switch. the first switch and the second magnet, and a. third circuit which includes the ilith switch, the fourth switch, and the second magnet.A

2. In'a device. of the class described, the combination with a gaivanometer consisting of the usual coil pivoted between the poles of a lpermanent magnet.- an indicating needle fastened to the coil. of afcontact piece for making electrical contact with the needle when the needle is deiiected against the contact piece, a circuit which includes the needle, the coil. and the contact piece, a. relay in the circuit, a second relay for changing the polarity oi' the circuit. said circuit from the opposite polarity back to'um given polarity. n relay in the 'circuit for actuating both means. a galvanometer in the same circuit for actuating the relay. and an larity,

' path 'of the needle with capable oi making electrical contact, electrical independent circuit for actuating the galvz,- nometer. i Y

4 In a device of the class described. the combination with an electric circuit, of means for changing the circuit from a given polarity to the opposite polarity, means for changing the circuit from the opposite polarity back to the given poa relay in Athe circuit for actuating both changing means, agalvanometer in the `same circuit for actuating a switch to close the circuit,

and anl independent circuit for energizing the galvanometer to closethe switch.

5. `In a device of the class described, the combination with va galvanometer, of an indicating. i

necdleactuatedby the piece 'with lwhich the contact. a relay.

galvanomcter, a contact needle makes electrical a source of electrical' energy,

a circuit which includes therelay, the contact.

l piece, the needle, the galvonometer and the source of electrical energy. means` actuatedby the relayfor changing the polarity ot the source, a second source of electrical energy. and a second circuit which .includes the gal'vanometer and thesecondsource. f

56. In a device ofthe classdescribed, the coinbination with a galvanometer Aof a needle actu-` ated by the galvanonieter-I a contact piecein the path of the needle with which the needle is capable of making. electrical contact, electrical means for forcing the contact piece out of the path of the needle, acircuitlwhich includes vthe galvanometer. the needle. the contact piece 'and the electrical means, and an independent circuit for energizing the needle against the contact piece.

7. In a device of the 'class described.' the combination with a galvanometer, ci a needle actuated by-the. galvanometer, a contact-piece in the which the needle is means forforcing the contact piece out of the path ot the needle,

switch actuated by the ilrst electrical means for closing a circuit through the second electrical means` A 8. In a device of the class described, tlie combination with a source-of electrical energy, oi

9. In a device ofthe class described, the com? bination with a galvanometer, of a. thermoa circuit which includes the Yelectrical means for changing the polarity .of

couple, an electric circuit which'includes the galvanometer and the couple in parallel. a source 4ot electrical energy in the circuit, means 'for changing the ratio of the electrical flow through the couple to the electrical ilow galvanometer, a switch actuated by the galvanometer for closing the circuit. a relay in' the circuit for actuating an electrical means to change the polarity oi' the circuit and a second and independent circuit which includes the ratio through the changing means, and the couple for energizing' the galvanometer cuit.

independently or the cir- 1o. rn a device of the class described, the cm- CII bination with a galvanometer, of a thermocouple for actuating the galvanometer, an electric circuit which includes the galvanometer and the couple in parallel, a source of electrical energy in the circuit, electrical means for changing the polarity of the source, a relay in series with the source for actuating the electricalv means, a switch actuated by the galvanometer for closing the circuit, and a resistance in series with the couple for changing the ratio of the electrical ilow through the galvanometer from the source with respect to the ilow through the couple from the source.

ll. In a device of the class described, the combination with an' electric circuit which includes a galvanometer and a thermo-couple,- of a second circuit which includes -the galvanometer, a relay and a source ci" electricalenergy in the second circuit, an electrical means controlled by the relay for changing the polarity ofthe source, and a switch operated by the galvanometerfor closing the second circuit.

12. In a device of the class described, the combination withan electric circuit which includes a galvanometer, a thermo-couple, a switch, and a potentiometer, of an indicating needle actuated by the galvanometer, a contact piece. for

intercepting the needle and making electrical contact therewith, electrical means for moving the contact piece out of -the path of the needle, a source of electrical energy, a second circuit which includes the source, the galvanometer, the needle, the contact piece, and the electrical means, a second electrical means for actuating the switch and simultaneously changing the polarity of the source. and.,` a second switch operated by the first electrical means for controlling the second electrical means substantially as described.

13. In a device of the class described, the combination .withI a galvanometer, of-a thermocouple, a potentiometer, a second potentiometer, a third potentiometer, a circuit which includes the galvanometer, the couple, the rst 'potentiometer and the second potentiometer, a second circuit which includes the galvanometer, the couple, the first potentiometer and the third potentiometer, an indicating needle actuated by the galvanometer, a contact piece for intercepting the needle and for making electrical contact therewith, electrical means for moving the contact piece out of the path of the needle, a source of electrical energy for energizing the electrical means, a third circuit which includes the source, the galvanometer, the needle, the contact piece and the electrical means, a switch for opening and closing the rst circuit, a second switch for opening and closing the second circuit, a switch mechanism for reversing the polarity of the source in one direction, a second switch mechanism for reversing the polarity of the source in the opposite direction, a second electrical means for opening the rst switch and the irst switch mechanism and simultaneously closing the second switch and the second switch mechanism, a third electrical means for closing the first switch and the iirstv switch mechanism and simultaneously opening the second switch and the second switch mechanism, and a third switch operated by the ilrst electrical means for actuating the second and third electrical means substantially as described.

14. In a device of the class described, the combination with a galvanometer, of a thermo-couple,

a' potentiometer, a second potentiometer, o third potentiometer, a circuit which includes the galvanometer, the couple, the irst potentiometer and the second potentiometer, a second circuit which includes the galvanometer, thecouple, the irst potentiometer and the third potentiometer, an indicating needle actuated by the galvanometer, a contact piece for intercepting the needle and for making electrical contact therewith, electrical means for moving the contact-piece out of the path of the needle.. a source of electrical energy for energizing the electrical means, a third circuit which includes the source, the galvanometer, the needle, the contact piece and the electrical means,a switch for opening and closing the ilrst circuit, a second switch for opening and closing the secondY circuit, a switch mechanism for -reversing the polarity of the source in one direction, a second switch mechanism for reversing the polarity ot the source in the opposite direction, a second electrical means for opening the first switch and the first switch mechanism and simultaneously closing the second switch and the second switch mechanism, a third electrical means for closing them-st switch and' the ilrst switch mechanism and simultaneously opening the second switch and the second switch mechanism, a third switch operated by the rst electrical means for controlling the second and third electrical means substantially as described, means for heating the couple, and means actuated by the second and third electrical means for turning the heating means oi and on.

15. In a device of the class described, the combination with an armature, of a mechanical means for forcing the armature to its normal position, electrical means for moving the amature, away from its normal position against the action of the mechanical means to a second position, a latch consisting of a catch and a finger for preventing the return of the armature to its normal position, but permitting a slight motion toward normal to a third position when the electrical means is deenergized, a second electrical means for releasing the latch to permit the mechanical means to force the armature back to its normal position when the rst` electrical means is del energized, a second mechanical means for forcing the latch to its normal position when the second electrical means is deenergized, a switch which is opened by the armature when forced into its second position by the ilrst electrical means, and closed by the armature when Aforced to either its third or normal position by the first mechanical means, a second switch which is closed bythe armature when in its second and third positions and opened by the armature when in its normal position, a third switch and a fourth switch which are opened and closed respectively by .the second electrical means when energized, and closed and opened respectively. by the second mechanical means when the second electrical means is deenergized, a ilfth switch t nd a sixth switch which taneously opening the ninth switch and forcing the contact piece out of the path of the needle, a third mechanical means for simultaneously closing the ninth switch and returning the contact piece to its normal position when the third electrical means is deenergized, a source of electrical energy, an electric circuit which includes the galvanometer, the needle, the contact piece, the third electrical means, the six'th switch, the source of electrical energy. and the fifth switch, a second circuit which includes the galvanometer, the needle, the contact piece, the third electrical means, the seventh switch, the source of electrical energy, and the eighth switch, a third circuit which includes the ninth switch. the source of electrical energy, the third switch and the first electrical means, a fourth circuit which includes the ninth switch. the source of electrical energy,

the third switch, the second switch,therstswitch. and the second electrical means. a iifth circuit which includes the ninth switch, the source of Yelectrical energy, the fourth switch and the second electrical means, a thermo-couple. and a sixth circuit which includes the galvanometer and the couple.

16. In a device of the class described, the combination with an armature, of a mechanical means for forcing the armature to its normal. position. electrical means for moving the armature away i rom its normal position against the action of the mechanical means to a second position, a latch consisting of a. catch and a finger for preventing the return of the armature to its normal position. but permitting a slight motion toward normal to a third position when the electrical means is deenergized, asecond electrical means for releasing the latch to permit the mechanical means to i'orce the arma'ture'back to its normal position when the rst electrical means is deenergized. a second mechanical means for forcing the catch to its normal position when the second electrical means is deenergized. a switch which is opened by the amature when forced into its second position by the first electrical means, and closed by the armature when forced to either its third or normal position by the first mechanical means, a second switch which is closed by the armature when in its second and third positions and opened by the armature when in its normal position, a third switch and a fourth switch which are opened and closed respectively by the second electrical means when energized. and closed and opened Vrespectively by the second mechanical means when the second electrical means is deenergized. a fifth switch and a sixth switch which are closed by the rst electrical means when energized and are opened by the first mechanical means when the first electrical means is deenergized. a seventh switch and an eighth switch which are opened by the rst electrical means when energized and closed by the first mechanical means when the first electrical means is deenergized, a galvanometer with an indicating needle. a contact piece the normal position of which is in the path of the needle and with which the needle is capable of making electric contact, a ninth switch, athird electrical means for simultaneously opening the ninth switch and forcing the contact piece out oi' the path of the needle. a third mechanical means for simultaneously closing the ninth switch and returning the contact piece to its normal position when the third electrical means is deenergized, a source of electrical energy, an electric circuit which includes the galvanometer, the needle, the

contact piece, the third electrical means. the sixth switch, the source of electrical energy. and the ilfth switch. a second circuit which includes the galvanometer, the needle, the contact piece, the third electrical means, the seventh switch, the source of electrical energy, and the eighth switch, a third circuit which includes the ninth switch, the source of electricalenergy. the third switch and the rst electrical means.' a fourthcircuit which includes the ninth switch. the source of electrical energy, the third switch, the second switch, the first switch, and the second electrical means, a fifth circuit which includes the ninth switch, the source of electrical energy, the fourth switch, and the second electrical means, a thermocouple, a sixth circuit which includes the galvanometer and the couple, a single pole double throw switch which is actuated in one direction by the ilrst electrical means and in the opposite direction by the second electrical means. and two adjustable potentiometers, one or the other of which is-cut into the thermo-couple circuit by means of the double throw switch. depending upon whether the first electrical means or the second electrical means is energized.

17. In a device of the class described, the combination with-a galvanometer, oi' an indicating needle which is deflected by the galvanometer, a contact piece extending into the path of the needle to prevent itsV deilectlon, an electro-magnet for forcing the contact piece out of the path of the needle, an electric circuit which includes the galvanometer and the magnet, and which circuit is closed by contact between the needle and the contact piece, electrical means controlled by the electro-magnet for changing the polarity of the circuit, a thermo-couple, and a separate circuit which includes the galvanometer and the couple for detlecting the needle against the contact piece.

18. In a device oi' the class described, the combination with a galvanometer. of an indicating needle actuated by the galvanometer, a contact piece in the path of the needle for making electrical contact with the needle, electrical means for forcing the contact piece out o1' the path of the needle, a source oi' electrical energy, a circuit which includes the needle, the contact piece, the electrical means, the source and the galvanometer. a shunt across the galvanometer which shunt includes a second source of electrical energy. and a resistance in series with the second source for adjusting the amount of current which passes through the shunt from the ilrst source.

19. In a device of the class described, the combination with a galvanometer, of an indicating needle actuated by the galvanometer. a contact piece in the path of the needle for making electrical contact with the needle, electrical means for forcing the contact piece out of the path of the needle. a source of electrical energy, a circuit which includes the needle, the contact piece, the electrical means, the source and the galvanometer, a shunt across the galvanometer which shunt includes a second source oi electrical energy. a resistance in series with the second source for adiusting the amount of current which passes through th'e shunt from the first source. and a potentiometer in the shunt for balancing the electro-motive force oi' the second source.

20. In a device of the class described. the combination with a galvanometer, of an indicating needle actuated by the galvanometcr. a contact piece in the path of the needle for making electrical contact with the needle, electrical means for forcing the contact piece out oi' the path of the needle, a source of electrical energy. a circuit which includes the needle, the contact piece, the electrical means, the source and the galvanoxneter, a relay for changing the polarity o! the circuit said relay being controlled by the electrical means, a shunt across the galvanometer which shunt includes a second source oi electrical energy, a resistance in series with the second source for adjusting the amount of current which passes through the shunt from the ilrst source, a potentiometer in the shunt for balancing the electromotive force of the second source. two auxiliary potentiometers for adding to or taking from the electro-motive force oi the second source, and a two-Way switch, actuated by the relay, for throwing one or the other of said two potentiometers in series with the second source.

FRITZ FREDERICK UEHMNG. 

